netbasd-alpha Multia Frequently Asked Questions

This document is a NetBSD/alpha FAQ for Multia/UDB systems, addressing common hardware and configuration problems.

Key Hardware Issues & Solutions:

• Freezing/Machine Checks (Heat Death): Multias are notoriously unreliable, often freezing due to overheating. The primary cause is a specific 74F623 TTL IC on the bottom of the board, which runs hot due to poor airflow.

  • Prevention: Always run the Multia vertically, heatsink the 74F623 chip, and consider modifying the fan to run at full speed or replacing it entirely with a higher CFM fan. Loose CPU heatsink nuts can also contribute.
  • Repair: Replace the faulty 74F623 chip with a cooler 74FCT or 74ABT series equivalent, with detailed instructions provided for a low-tech lab.

• Bogus PCI Devices: Systems may print "unknown vendor 0x200d product 0x00c2" errors and misidentify the TGA framebuffer. This is a known firmware bug with no official fix from DEC.

• Dead Clock Battery: A dead battery can prevent the Multia from booting. Replacements (e.g., Nesco AA102-4, Rayovac 840) are recommended.
• Sound Not Working: This can often be fixed by changing a line in the kernel config from drq 0 to drq 3 for the WSS* device.

Other Questions & Explanations:

• Performance ("166 MHz so slow"): The 166MHz Alpha CPU (21066/A/8) is comparable to a Pentium-100 for integer tasks, though better for floating-point. Overclocking is strongly discouraged due to the Multia's inherent heat issues. Jumper settings for different CPU speeds (including unsupported ones) are provided for reference.
• Netboot Failure: Firmware revision 3.8-3 has a bug that prevents netbooting, despite earlier versions reportedly working. No official fix exists. Workarounds include custom floppy boots, external drives, or specific netboot executables.
• IDE Drives: A 44-pin connector for 2.5" laptop IDE drives is present, but the Multia's SRM console cannot boot from an IDE drive. Booting must occur from floppy, SCSI, or network, after which the kernel can mount IDE devices.
• Firmware Updates: Updating firmware is generally not recommended unless absolutely necessary, as it can be difficult to revert, and newer versions (like 3.8-3) may introduce netbooting bugs.
• Video Modes: Multias use a fixed-frequency framebuffer with modes set via jumpers. A table lists jumper settings for various resolutions, refresh rates, and pixel clocks.
• Other Jumpers: Tables provide functions for other motherboard jumpers, including those for the mini console, powerup sequence, floppy boot failsafe, and halt/reset.
• Second Serial Port: The Multia's single DB-25 connector carries two serial ports. A pinout is provided for users to create a splitter cable to access the secondary port.
• Model Numbers: Common model numbers (e.g., VX40L-F2, VX42B-F2) are listed with their CPU speeds, cache, and SCSI drive sizes.